QT dispersion and P wave dispersion in schizophrenia

BACKGROUND: The difference between maximum QT (QTmax) and minimum (QTmin) on electrocardiography (ECG) is known as QT dispersion (QTd). An increase in QTd carries the risk of ventricular arrhythmia and subsequent death. P wave dispersion (Pd) shows the difference between maximum P (Pmax) and minimum P (Pmin). Prolonged P wave duration and an increase in Pd are a risk for irregular electrical transmission and atrial fibrillation. OBJECTIVES: The aim of this study was to examine QTd and Pd values which indicate atrial fibrillation and ventricular arrhythmia in schizophrenia patients with whom cardiovascular diseases (CVD) are seen at a higher rate than the general population.

METHOD: The patient group consisted of 30 male patients diagnosed with schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and receiving treatment either as inpatients or outpatients in the Mental Health and Diseases Hospital. The patient group had no other psychiatric, neurological or physical disease. The control group comprised 30 age-matched healthy males with no history of neurological, psychiatric, or physical disease.

RESULTS: The cases in both groups were all males and there was no difference between the groups in respect of age. Corrected QTd was determined as 25.55 ± 13.18 (ms) in the control group and 54.26 ± 8.46 (ms) in the patient group (p < .001). Pd was determined as 36.22 ± 10.08 (ms) in the control group and 46.32 ± 5.87 (ms) in the patient group (p < .001). The differences in the values between the groups were statistically significant.

DISCUSSIONS: The QTd and Pd values which show increased CVD risk were found to be significantly greater in schizophrenia patients than in the healthy control group. However, there is a need for further studies to determine whether this is a result of the nature of schizophrenia or the effect of the treatment drugs used. Thus, future studies could be planned to compare the QTd and Pd values of treated and untreated schizophrenia patients.